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All 25 Flashcards — Threats to biodiversity
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Question
What is the difference between direct and indirect threats?
Answer
Direct threats target species directly (e.g., poaching), whereas indirect threats damage ecosystems as a side effect (e.g., habitat loss, climate change).
💡 Hint
Direct = species; indirect = habitat/system.
Question
What is an invasive species?
Answer
An invasive species is a non-native organism introduced by humans that spreads rapidly and harms native ecosystems.
💡 Hint
Non-native + harmful.
Question
What is the main driver of biodiversity loss today?
Answer
Human activity is the main driver, including habitat destruction, overexploitation, pollution, and climate change.
💡 Hint
Mostly human causes.
Question
What is the tragedy of the commons?
Answer
It occurs when individuals overuse a shared resource for short-term gain, leading to long-term depletion and collective loss.
💡 Hint
Shared resource overused.
Question
List four major human threats to biodiversity.
Answer
Habitat loss, overexploitation, pollution, climate change, and invasive species are major threats.
💡 Hint
Think HIPPO + climate.
Question
Give two examples of direct threats to biodiversity.
Answer
Overharvesting and poaching are direct threats because they remove individuals from populations.
💡 Hint
Target the species.
Question
Why are invasive species especially damaging?
Answer
They disrupt ecosystem balance by outcompeting native species and altering food webs.
💡 Hint
Disrupt balance.
Question
Why are invasive species often successful in new environments?
Answer
They may lack natural predators, compete strongly for resources, or reproduce quickly in the new ecosystem.
💡 Hint
Few predators + strong competition.
Question
Why does the tragedy of the commons occur?
Answer
Because individuals act in their own short-term interest while the costs of overuse are shared by everyone.
💡 Hint
Short-term gain vs shared loss.
Question
How does habitat loss threaten species?
Answer
Habitat loss reduces available food, shelter, and breeding space, causing population decline and increased extinction risk.
💡 Hint
Less space + fewer resources.
Question
Give two examples of indirect threats to biodiversity.
Answer
Habitat loss and climate change are indirect threats because they alter ecosystems and affect many species at once.
💡 Hint
System-level impacts.
Question
Why are small populations more vulnerable to extinction?
Answer
Small populations have lower genetic diversity, are more affected by random events, and may struggle to reproduce successfully.
💡 Hint
Small size = high risk.
Question
Give one biodiversity-related example of the tragedy of the commons.
Answer
Overfishing in open oceans where no single country controls the resource can lead to stock collapse.
💡 Hint
Open-access overuse.
Question
How can invasive species reduce native biodiversity?
Answer
They outcompete, prey on, or bring diseases to native species, causing population declines or extinctions.
💡 Hint
Competition + predation + disease.
Question
Why do unmanaged shared resources often decline?
Answer
Because without regulation, individuals maximise personal benefit, leading to overuse and depletion.
💡 Hint
No rules = overuse.
Question
Why can invasive predators have strong ecosystem effects?
Answer
Without natural enemies, invasive predators can rapidly reduce prey populations and disrupt entire food webs.
💡 Hint
No natural control.
Question
Why do combined impacts increase collapse risk?
Answer
Multiple interacting threats reduce resilience and make ecosystems less able to recover.
💡 Hint
Stacked pressures.
Question
How can management reduce the tragedy of the commons?
Answer
By introducing regulations, quotas, enforcement, or shared agreements that limit overuse and promote sustainability.
💡 Hint
Rules + enforcement.
Question
Give one example of a direct human threat to a species.
Answer
Poaching or overharvesting directly reduces population size and can push species toward extinction.
💡 Hint
Directly targets species.
Question
Why do indirect threats often affect many species at once?
Answer
Because they change habitat conditions or ecosystem processes that multiple species depend on.
💡 Hint
Shared habitat impact.
Question
Exam link: why is early intervention important in biodiversity protection?
Answer
Because preventing decline is easier and cheaper than restoring ecosystems after severe damage or species extinction.
💡 Hint
Prevention > restoration.
Question
Exam tip: in a 4-mark “explain a threat” question, what should you include?
Answer
Name the threat, describe how it affects species or habitats, and explain the consequences for population size or ecosystem stability.
💡 Hint
Name + mechanism + consequence.
Question
Why are invasive species considered both a direct and indirect threat?
Answer
They directly harm native species but also indirectly alter ecosystem structure and processes.
💡 Hint
Species-level + ecosystem-level effects.
Question
Why do multiple combined threats reduce ecosystem resilience?
Answer
When several pressures act at once (e.g., habitat loss plus climate change), recovery is harder and tipping points are more likely.
💡 Hint
Multiple stresses amplify risk.
Question
Why does habitat fragmentation reduce resilience?
Answer
Fragmentation isolates populations, limits gene flow, increases edge effects, and reduces overall ecosystem stability.
💡 Hint
Isolation + edge effects.
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